Hello, I would like to use the usb_hid sample code from Keil, to see how the USB works. I could create a project in uvision and build it and generate hex file and download it to my evaluation board, which has LPC2148 on it, but when I connect the usb cable to it, I dont get anything on Device manager and when I check it, is not the same as what is expected. would you please help me to understand this problem. I am not sure, If I have to do any change to the code or not?
Thanks Neda
> usb_hid sample code from Keil
Which one are you referring to? There are so many "KEIL HID examples", one included in MDK-ARM, another one included in NXP code bundle, one on Keil download page ( http://www.keil.com/download/list/arm.htm ), etc.
Most likely, it's hardware problem(s). Identify the target board of the "HID example". On the board schematic, check these items. And compare them with your board. - Crystal frequency - D+ pull-up circuitry
Keil MCB2140 has fixed pull-up resistor (R35: 1k5) http://www.keil.com/mcb2140/mcb2140-schematics.pdf
Tsuneo
Hello Tsuneo, thanks for your reply. I am using the USB_HID example for the MCB2140 in the Keil. I also check the usbhw.c and it set the frequency as 12Mhz for Fsc and 48MH for USB clock, which is the same as mine. the Pullup resistor on my board is 1.5k which is between D+ and 3.3v regarding the D+ pull up, where in the code, should I make a change? thanks for your help Neda